Foot switch



H, P. FOOT SWITCH Filed May 25, 1923 Patented Apr. 19, 1927.

UNITED STATES PATEN'i` OFFICES..

HECTOR P. MAGLAGAN, OF CHICAGO, ILLINOIS, ASSIIErlTCKLtr TO liIoIN'IOSI-Il ELECTRICAL CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

FOOT SWITCH.

Application filed May 25,

My invention relates to an improved form of toot switch for controlling desired electric circuits, particularly high tension circuits used in electro-therapeutic work.

In many instances of the use of the electric current it is desirable to control the same by means of a toot switch leaving the hands or the operator free to direct the operation of the apparatus, and in such cases it requently happens that it is desirable to be able to el'ect two conditions o'l application ot the electric current, lirsta condition by which the current is supplied to the operated apparatus synchronously with movement or pressure or the foot, so that the current is applied by pressure or the `foot against the switch and interrupted when the aressure or the toot is released, and secon a continuous application of the current upon a pressure of the foot against the switch whether the pressure of the foot is continued or not, in which latter case a subsequent and different operation of the switch by the Yfoot is required to interrupt the current flow. This is particularly the case in connection with the application or electric current of various modalities for electro-therapeutic purposes. For convenience in the remaining description ol the present invention the two different conditions of application of the current will be referred to as momentary and continuous applications respectively.

By my invention I provide a foot switch convenient for operation by the foot in either one of two ways, first by a pressure on one part of the switch, contacts or' the switch are operated tor momentary application and second by pressure on a second part ot' the switch, contacts ot' the switch are operated for continuous application; in thelatter case I find it convenient to interrupt the continuous application by pressure on therpart oit' the switch securing momentary application; the two controls referred to kare secured by a conformation ot' the switch contacts themselves such that the contacts operative iior momentary application do not retain the moving parts in their operated position, whereas the contacts .tor continuous application retain the moving parts in their operated position, thus maintaining the closure of the circuit until the operating mechanism is actuated to release the retained contacts. In carrying out my invention I iind it convenient to secure the 1923. Serial No. 641,379.

two operations referred to, by means of a single treadle operated in a first direction for momentary application and in a second direction iior continuous application. My invention generically theretor consists or' a toot operated switch having contacts elicoting momentary application for motion in one direction or the actuating mechanism and continuous application tor motion in a second direction of the actuating mechanism. j

By my .invention I preferably locate the treadler portion or' the actuating mechanism at a substantial distance from the switch contacts and connect the treadle mechanism with the switch contacts by means or' an insulating member Vwhich is desirable for high tension electro-therapeutic workv to insure that the operator will not be affected by the high voltage or high frequency current employed.

My invention will best be understood by reference to the accompanying drawings showing a preferred embodiment thereof, 1n whichf Fig. l shows my improved switching mechanismin plan view vwith the casing partly broken away to more clearly show the arrangement of the switch contacts,

Fig. 2 is a sectional view of the parts shown in Fig. ,l taken along the line 2--2,

Fig. 3 is a sectional view of ythe parts shown in Fig. l taken along the line 3-3, and

Fig. 4. is a sectional View of the contact mechanism shown in Fig. 1 taken along the line i-4r Similar numerals refer to similar parts throughout the several views.

As shown in the drawings, my switch construction consists ot' a base l0 preferably of insulating material, for example slate, from which two supporting posts 1 1 and l2 project upwardly to pivotally support lugs 13 and 14.- respectively. The lug 18 projects downwardly from a treadle 15 provided with two laterally extending portions 153L and 15, projecting in opposite directions from the center line of the treadle. The lug lll projects downwardly from and .is rigidly secure-d to aplate 16, preferably ot metal, and the plate 16 and the treadle 15 are rigidly connected by a bar 17 of insulating material, for example hard rubber or the equivalent, so that the treadle and all of the metal parts associated therewith are preferably at a considerable distance from the metal plate 16. The plate 16, bar 17 and treadle 15 thus form a rocking structure which may be tilted in one direction by downward pressure on the extension 15CL ot the treadle and in the opposite direction by downward pressure on the extension 15 of the treadle.

rlhe plate 16 is preferably rectangular' and under its edge portions the. base 10 supports a first pair of contacts 18, 18 on one side of the axis through the pivotal supports referred to, and a second pair of contacts 19, 19il on the other sidel of said axis. Said contacts project upwardly from the base and arc rigidly secured thereto, the contacts 18 and 19l being electrically connected by a conductor 2() and the contacts 18a and 19 being connected by an electrical conductor 21 insulated trom the conductor 20. The contact 18 is connected with one conductor 21 of the circuit controlled by the switch and the contact 19 is connected with the other conductor 22 of said circuit. As a result of the construction last described, electrically connecting either the contacts 18 and 18a or 19 and 19L serves to electrically connect the conductors 21 and 22 extending to the circuit controlled by the switch.

The plate 16 carries on its lower surface over the ends of the contacts 18 and 18a, a contact plate 23, which as more clearly shown in Fig. 2, is pivotally supported at its mid-portion from the plate 16 and which, when the extension 15a is depressed, makes electrical connection between the contacts 18 and 18a. This insures that the plate 23 will make contact with both of the contacts 18 and 18a when the corresponding edge of the plate 16 is depressed. The plate 16 also has extending from its lower surface above the ends of the contacts 19 and 19atwo switch blades 24, 2% arranged to enter the upper split ends of the jaw contacts 19 and 19a which engage and by their spring action retain the blades 24, 24a when the extension 15b of the treadle is depressed.

A bent fiat spring 25 is located between the treadle 15 and the base 10, which is eliective to hold the treadle 15 and plate 16 in substantially parallel relation with the base 10 when pressure is exerted upon neither of the extensions 152l or 15". The tension on the spring 25 is sufficient to move the plate 16 and the treadle 15 to horizontal position after depression of the extension 15a, thus moving the contact plate 23 from engagement with the contacts 18, 18a and opening the circuit, but it is insufhcient to move the blades 24 and 2st-a from engagement with the contacts 19 and 19 after depression of the extension 151. After the extension 15b has been depressed and the plate 16 is held in its tilted position by the act-ion between the contact blades 24 and 24` and the cretacts 19,

19a as above referred to, the circuit remains closed until it is opened by a subsequent operation, which is eti'ected by placing suliicient pressure on the extension 15a to move the blades 241 and 24a from engagement with the contacts 19, 19, upon which the spring 25 moves the treadle 15 and plate 16 to substantially parallel relation with the base 10, for which condition ample clearance is provided between the contacts and circuit closing devices oit the switch to maintain the circuit through the conductors 21 and 22 in opened condition.

The contact mechanism is preferably enclosed in a housing 26 secured to the base in any suitable manner, for example by screws, to protect said contact mechanism, said housing having an aperture 26l through its side wall to permit the bar 17 to extend from the plate 16 to the treadle 15.

For convenience the extensions 15a and 15b may bear suitable designations or indicating characters for example M and C to indicate the operation secured by depression of each extension, to-wit momentary application and continuous application.

From the construction described it will appear that my improved switch is of simple construction, that it is substantial throughout, that it effectively protects the operator from electric shock or charge and that no auxiliary devices are employed or required to effect continuous application as distinguished from momentary application and furthermore that the change of position of the foot of the operator required to produce momentary application from that required to produce continuousapplication is Sullicient so that confusion between the two modes of application is readily avoided.

lVhile I have shown my invention in the particular embodimentabove described, it will be understood that I do not limit myself to this exact construction as I may employ equivalents known to the art at the time of the iiling of this application Without departing from the scope of the appended claims.

What I claim is:

1. In a foot switch, the combination of an elongated base of insulating material, a pivotal support carried by each end o said base, the pivot portions of said supports being in alignment with each other, a treadle mounted for oscillation on one of -said supports, a plate mounted for oscillation on the other of said supports, metal contact bars carried' by said plate, insulated contacts carried by the base for engagement by said bars when said plate is oscillated, and a bar of insulating material rigidly connecting said treadle and said plate, the separation of said treadle and said plate being such as to prevent leakage of high tension current from said contact bars to said treadle.

2. In a foot switch, the combination of an elongated base of insulating material, a pivotal support carried by each end of said base, the pivot portions of said supports being in alignment with each other, a treadle mounted for oscillation on one of said supports, a plate mounted for oscillation on the other of said supports, metal contact bars carried by said plate, insulated contacts carried by the base for engagement by said bars when said plate is oscillated, and a bar of insulating material rigidly connecting said treadle and said plate, one of said contact bars having pivotal connection between its ends with said plate insuring contact between both of its ends and the correspondinr ones of said insulated contacts when said plate is oscillated to move said pivoted con* tact bar against its contacts.

3. In a foot switch, the combination of an elongated base of insulating material, a pivotal support carried by each end of said base, the pivot portions of said supports being in alignment With each other, a treadle mounted :tor oscillation on one of said supports, a plate mounted for oscillation on the other of said supports, metal contact bars carried by said plate, insulated contacts carried by the base for engagement by said bars when said plate is oscillated, and a bar of insulating material rigidly connecting said treadle and said plate.

4. In a foot switch, the combination of an elongated base of insulating material, a pivotal support carried by each end of said base, the pivot portionsr of said supports being in alignment with each other, a treadle mounted for oscillation on one oit' said supports, a plate mounted for oscillation on the other oi said supports, metal contact bars carried by said plate, insulated contacts carried by the base for engagement by said bars when said plate is oscillated, a bar of insulating material rigidly connecting said treadle and said plate, and al flat spring having one end rigidly secured to said base and its other end engaging said oscillatory structure on opposite sides of its axis of oscillation, whereby oscillating said treadle in .either direction depresses the free end of said spring.

In witness whereof, I hereunto subscribe my name this 15th day of May, A. D. 1923.

HECTOR P. MACLAGAN. 

